Automatic hemming machines

ABSTRACT

A system is provided for enabling a sewing machine to fold and secure edge portions of successive work pieces uniformly. More specifically, automatic mechanism is provided for the hemming of shirt collar bands and the like, each collar band being introduced and appropriately registered and controlled with respect to operating instrumentalities to enable the hemming to be precisely executed from one extremity of a collar band tip to the other whereupon the sewing thread is severed. The mechanism is particularly well adapted to cooperate cylically in the coordinating of an automatic fabric feeder and the sewing machine.

Elite States Patent [191 Gray [451 June5, 1973 [54] AUTOMATIC HEMMING MACHINES [75] Inventor: Richard W. Gray, Marbl head,

Mass. H

[73] Assignee: USM Corporation, F lemington, NJ.

[22] Filed: July 30, 1971 [21] App]. No.: 167,690

[52] U.S.Cl ..l12/l41 [51] Int. Cl. ..D05b 35/02 [58] Field of Search ..1l2/l4l, 136, 102, 112/90, 86,121.15,121.12, 121.11

[56] References Cited UNITED STATES PATENTS 2,751,867 6/1956 Washburn et a]. 1 12/134 3,543,706 6/1969 Reid ..112/l4l Primary Examiner-H. Hampton Hunter Attorney- Richard B. Megley, Vincent A. White and Carl E. Johnson [57] ABSTRACT A system is provided for enabling a sewing machine to fold and secure edge portions of successive work pieces uniformly. More specifically, automatic mechanism is provided for the hemming of shirt collar bands and the like, each collar band being introduced and appropriately registered and controlled with respect to operating instrumentalities to enable the hemming to be precisely executed from one extremity of a collar band tip to the other whereupon the sewing thread is severed. The mechanism is particularly well adapted to cooperate cylically in the coordinating of an automatic fabric feeder and the sewing machine.

8 Claims Drawing Figures PATENTEUJUH 5 I915 SHEET 10F 4 fnvenzor Richard W Gray By his Attorney AUTOMATIC HEMMING MACHINES CROSS REFERENCE TO RELATED APPLICATION An application Ser. No. 19,257 filed Mar. 13, 1970 in the names of R. W. Gray et al, now US. Pat. No. 3,616,771 relates to work guidance mechanism for a sewing machine and is assigned to the assignee of the present invention.

BACKGROUND OF THE INVENTION In the apparel industry one sewing operation wherein the exercise of careful judgment is involved, and indeed commonly insisted upon, is the hemming of shirt collars. In particular mens shirt collar bands are generally manually hemmed from one tip to the other, especially criticalattention being directed to initiating and terminating the hem so that each collar band enhances the style of its shirt and will provide a neat appearing collar when worn. While it is found that the hemming is ordinarily fairly uniform along a collar margin between the collar tips, it is difficult and tedious manually to provide the hem folding and forming and sewing with precision right out to the critical extremities or wings of the collar band.

While the invention is herein illustrated as applied to feeding, registering and down-turn hemming of collar bands, it will be understood that the invention is not thus limited but has application to automatic systems involving the folding and/or hemming of numerous garment components, towels, and other articles of flexible sheet material whether of fabric or otherwise.

In the prior art, attachments or units have been provided for use in conjunction with sewing machines for facilitating conveyance and folding of flexible sheet material relative to the operating zone ofa needle. One such machine is disclosed, for example, in U. S. Letters Patent No. 3,534,954 issued Oct. 20, 1970. While many of the known mechanical arrangements facilitate manual folding operations, no automatic apparatus is known to be available for performing precision hemming from one predetermined point or extremity to another of successive work pieces.

In an automatic processing system the accuracy of input feed may affect subsequent operations such as hemming. Less uniform results are produced, for instance, if an otherwise accurate infeeding mechanism must cylically deliver from an irregular stack of work pieces. In one aspect, this invention accordingly seeks to provide, in combination with an automatic feeder, an improved means for compensating for non-uniform work piece positioning.

SUMMARY OF THE INVENTION In view of the foregoing it is an object of this invention to provide in combination with a sewing machine or the like an automatic hemming system for successively presenting and guiding work pieces to be operated thereon between predetermined points including its marginal extremities.

Another and more specific object of the invention is to provide for use with a sewing machine having a work feeding means, an improved, automatic collar hemming apparatus adapted to guide the work directly to the feeding means.

To these ends, and in accordance with a feature of the invention, there is provided in combination with a margin securing means including a bed and work feeding means (such as a conventional stitcher provided with a needle, presser foot, and feed dog), a carriage reciprocable laterally toward and from the stitcher parallel to the bed, said carriage including a translatory first work engageable clamp, a hemmer, and a sensor fixedly spaced ahead of the first clamp and responsive to traverse of the leading edge of a work piece to be hemmed for actuating said first clamp, a nontranslatory second work clamp cooperative with the bed, and automatic control means for advancing the carriage while the second clamp is operative until the sensor responds to said leading edge and then releasing the work from the second work clamp and actuating the first clamp to cause the carriage and the first clamp to advance the work to the work feeding means and start the stitcher, whereupon the first clamp is released.

As herein shown additional novel features and combinations of parts reside, for instance, in the provision in the above described combination of pneumatic means for progressively positioning and forming the work margin in the hemmer, adjustable spacing of the leading end sensor and the translatory clamp along the line of feed, and associated controls for supplying air flow guidance to the hemmer, regulating advance and retraction of the carriage, effecting time in operation of a thread severing device, and coordinating operation of the apparatus with a cylically operable fabric feeding machine.

Relative movement of the hemmer with respect to the work piece to be marginally folded enables avoidance of pushing on the cloth itself which customarily causes bunching up or jamming of small pieces or portions of the cloth.

BRIEF DESCRIPTION OF DRAWINGS The foregoing and other features of the invention will now be more particularly described in connection with an illustrative embodiment and reference to the accompanying drawings thereof, wherein:

FIG. 1 is a plan view, partly in section, of a collar band hemming machine, three successive initial or loading positions of the band to be hemmed being shown;

FIG. 2 is a plan view corresponding to FIG. 1 showing the next stage wherein a carriage is advanced with its translatory first work clamp, a hemming device and a control sensor leftward toward a sewing machine;

FIG. 3 is a view corresponding to FIG. 2 showing the work advanced leftward by the first clamp, the control sensor having effected release of a second work clamp;

FIG. 4 is a view in side elevation showing a collar band being fed into the machine as in FIG. 1, both work clamps being disengaged;

FIG. 5 is a view corresponding to FIG. 4 but on a larger scale and with the collar band partly introduced into the hemming device;

FIG. 6 is a view similar to FIG. 5 but taken at a later stage wherein a leading portion of the downturned hem has been formed;

FIG. 7 is a vertical section of the hemmer indicating pneumatic means for edge guiding and forming the hem;

FIG. Sis a view in front elevation of the machine; and

FIG. 9 is a perspective view of the machine showing a hemmed work piece passing a thread cutting member as a succeeding work piece is advanced to be hemmed.

DESCRIPTION OF PREFERRED EMBODIMENT The invention will now be described as embodied in a collar making system employing a sewing machine 10 (partly shown in FIG. 9) having stitch forming means including a reciprocable needle 12 (FIGS. 1-3, 8, 9), a presser foot 14, and cooperative feed dog 16 (FIG. 9) disposed in conventional relation to a flat bed 18. Preferably, and as shown, successive work pieces such as unfinished shirt collar bands C are cylically fed into the system by means such as the automatic feeder disclosed in U. S. Letters Patent No. 3,53l,l03 issued Sept. 29, 1970 on an application filed in the name of R. R. Walton. The feeder employs a pair of fabric pick-up devices 20, 22 reciprocable between a pick-off position such as'shown at 24 (FIG. 1) to a release position indicated at 26. It will become apparent that the invention may be used in widely different embodiments including hand fed arrangements and ones wherein other margin securing means, e.g. adhesive applicators, are employed for processing various types of work pieces.

At the delivery position 26 the collar band C interrupts air flow in a stationary ply sensor 28 (FIG. 1) fixedly overhanging the bed 18 and a light beam 30 directed downwardly from a sensor 32 carried by a laterally reciprocable carriage 34 about to be further described. In the drawings only about half of the length of the collar band C is shown, it being understood that it is substantially symmetrical and has a leading end tip T between which and a trailing tip end (not shown except in FIG. 9) the longitudinal margin M is to be hemmed. The interruption of the sensor 28 by the presented fabric ply is adapted to effect its release from the devices 20, 22 and initiate their return for reloading.

For purposes hereinafter explained, the carriage 34 additionally supports a translatory first work clamp 36 (FIGS. 4-6, 8 and 9) mounted on the lower end of a piston rod 38. This clamp 36 has a spring feed finger 37 which projects toward work engaging relation from an air operated cylinder 40 that is secured by a C clamp 42 and rearwardly projecting bracket 44 to the carriage 34. Between the translatory clamp 36 and the sensor 32 the carriage supports an angular bracket 46 to the lower end of which is secured a hemmer generally designated 48 (see FIGS. 5, 6, 9). The latter may be of different forms but, as illustrated, is of down-turn U-bend configuration having an inlet or mouth portion 50 comprised of spaced sheet metal plates 52, 54, a bend portion 56 for guiding the work substantially parallel to the direction of feed, and an integral L-shaped edge gage portion 58. The upper plate 52 threadedly receives an inlet plug 60 (FIG. 7) adapted to be coupled to an air supply tube 62. A nut 64 and a lock nut 66 hold the plug 60 non-rotatably on the hemmer, and a lip 68 of the plug is adapted, upon signal, to direct air flow parallel to the plate 52 over the collar band C to urge it first from the position 26 (FIG. 1) toward the position 69 of FIG. I and shown in FIG. and thereafter into folded form as indicated in FIG. 6. I

The sensor 32, for setting-up purposes, is adjustably mounted on the carriage 34 to direct its beam 30 ahead of the translatory clamp 36 by a normally fixed spacing t appropriate to the particular control circuitry. For this purpose a block 70 of the sensor is slidably mounted on a guide rod 72 supported on the carriage 34. The latter is movable laterally between cooperative guide rolls 74, 74 (FIG. 4) rotatably supported in a bracket 76 secured to the bed 18. For thus reciprocating the carriage a cylinder 78 (FIGS. 2, 3, 8 and 9) secured to the bed is fitted with air delivery tubes 79, 81 and a dual acting piston (not shown) coupling a piston rod to the carriage. The right-hand limit of carriage travel is determined by the length of the piston stroke, the piston being buffered; the extreme limit being fixed by abutment of its right extremity with a lug 82 as indicated in FIG. 8. The extreme left-hand limit of carriage travel is similarly determined by a lug 84, the lugs 82, 84 being those supporting a carriage guide rod 85. The arrangement is such that in its initial righthand position the carriage 34 is retracted from the needle 12 and the left tip T of the collar does not overlay a reflective tape 86 (FIGS. 1, 2) on the bed cooperative with the sensor 32 as will be explained.

With the piece C introduced into the machine as shown in FIG. 1 at 26 a non-translatory work clamp 88 is retracted and disengaged until its operating cylinder 90 is signaled as will be explained. The clamp 88 depends from the end of a piston rod 92 and is yieldingly urged into operative position against resistance of a return spring (not shown) by means of air admitted to the cylinder 90 under pressure via a tube 94. As mentioned above the sensor 28, being interrupted by the presented work, effects retraction of the pick-ups 20, 22 leaving the collar band C substantially in the position 26 but, as derived from an irregular stack, possibly positioned up to about 3/16 inch to right or left of a median position. Practice of the invention compensates for this deviation. The actuation of the sensor 28, due to air flow interruption by the work producing a drop in air pres sure, also causes air to flow through the hemmer plug 60 to form the hem in a lead portion of the piece C, and then clamps the piece to the bed in stationary position 69 (FIG. 1) by means of lowering the rod 92 and hence the clamp 88. The further steps in a cycle of operations will next be reviewed, it being assumed the carriage 34 is initially in its right-hand starting position.

The interruption of the sensor 28 and resultant in pressure drop also is used to signal for advance of the carriage 34 by admitting pressurized air via the tube 81 to the cylinder 78. The sensor 32, hemmer 48, and mo bile clamp 36 accordingly are jointly moved laterally with the carriage relative to clamped work and toward the stitch forming zone of the needle 12 as shown in FIGS. 2 and 3. The arrangement is such that the hemmer 48, when moving laterally relative to the stationary work being held by clamp 88, is enabled to fold the margin of the work C right up to and including its tip portion. When thereafter the beam 30 rides off the tip of the piece C and gives a signal by reflection from the reflector 86, the clamp 88 is thereupon released, to free the work and the mobile clamp 36 (more accurately, its feed finger 37) made to engage the work C to advance it laterally with the moving carriage 34. The folded tip of the work margin as seen in FIG. 6 is moved laterally by the finger 37 to the exact extent, i.e. fixed distance, required to place the tip between the cooperative presser foot and the feed dog, the edge gage portion 58 being accomodated by a cut away portion of the presser fo'ot'as shown in FIG. 3. At this point in the cycle a leading side surface 96 (FIG. 3) of the carriage 34 blocks off a pneumatic sensor 98 bracketed on the machine signaling the sewing machine 10 to commence stitching and feeding the piece C in usual manner. The mobile clamp 36, after a momentary delay, is disengaged from the work and the entire marginal length is hemmed and sewn, the trailing portion of the hem H being indicated in FIG. 9.

When the ply sensor 28 sees" the trailing edge of the piece C and is no longer interrupted thereby, the following events occur after a time delay: the carriage 34 is returned to its starting position; the machine stops stitching; and air flow to the hemmer 48 ceases. A final step is that a beam from a suitably mounted chain cutter sensor 100 (FIGS. 1-3 and 9) responsive to passage of the trailing end of the piece C actuates a fluid pressure operated cutting blade 102. The latter cooperates with the bed, or a hardened insert thereon, to sever the thread chain thereby freeing one hemmed collar band as a new work piece C is being delivered for hemming. A conveyor may be provided for removing the successive work pieces, a mechanism preferably cooperating therewith to tension each piece lengthwise thereby facilitating the thread severing.

A cycle of the hemmer whereby differences in initial work positioning due to delivery by an automatic feeder from an irregular stack, or otherwise, are compensated for will now be reviewed. The pick-up devices 20,22 are caused to release the work C at the delivery position 26 when a presented margin of the work interrupts air flow in the ply sensor 28. As shown in FIG. 1 the beam 30 is also interrupted at this time by the work, the carriage 34 now being fully retracted to its right hand starting position and engaging the lug 82. The non-translatory clamp 88 and the translatory clamp 36 have previously both been retracted from the bed 18. After the interrupted sensor 28 has signaled for air flow through the plug 60 to shift the work inwardly to its position 69 (FIG. 1) wherein a leading marginal portion is formed in the hemmer 48, the clamp 88 is caused by signal from the sensor 28 to engage the work C to hold it against translation on the bed 18. The air pressure drop in the sensor 28 at its interruption is now also employed to signal for lateral advance of the carriage 34 relative to the work C, the pressurized air then admitted to the cylinder 38 via the tube 81 thus jointly shifting the sensor 32, the hemmer 48, and the inoperative mobile clamp 36 linearly toward the needle 12 as the work C is held stationary. The relatively moving hemmer 48 accordingly folds the margin of the work right up to its lead tip T. The carriage 34, in next moving the beam 30 just beyond the stationary folded tip T, causes reflection of the beam 30 from the reflector tape 86 back to the sensor 32. As a consequence of this reflection sensing, the non-translatory clamp 88 is signaled by the sensor 32 to retract and disengage the work C thus permitting its movement, and the laterally moving feed finger 37 of the mobile clamp 36 is almost simultaneously caused to engage and advance the now otherwise unclamped work along with the moving carriage 34. Hence the folded leading tip of the work, when the carriage side surface 96 blocks off the sensor 98, has been moved a fixed distance sufficient to be disposed between the feed dog 16 and its cooperating presser foot 14. Blockage of the sensor 98 by the carriage surface 96 signals the sewing machine 10 to operate, i.e. to commence hemming on the leading tip T. After a momentary time delay the hitherto mobile clamp 36 is released from the work and its entire margin is hemmed as it is progressively drawn through the hemmer and into the operating zone of the needle. When the sensor 28 is no longer interrupted by the trailing work C, and

after a time delay, the machine 10 stops stitching, the carriage 34 is returned to the right as viewed in FIG. 1, air to the hemmer 48 ceases its flow, and the blade 102 severs the thread chain in response to a signal from the sensor 100. The cycle is then repeated with respect to the next work piece C presented.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. The combination with a sewing machine having stitch forming instrumentalities, a bed, and work feeding means for advancing a work piece linearly on the bed through the operating zone of said instrumentalities, of apparatus for hemming the margins of successive work pieces comprising, a carriage mounted for movement parallel to the bed and toward and from the instrumentalities, a first and second work engageable clamp cooperative with the bed, the first of which clamps is carried by the carriage, a hemmer mounted on the carriage ahead of the first clamp and adapted to fold the margin of the work to be hemmed, power means for moving the carriage, and control means, responsive to lateral movement of the hemmer and the first clamp to within a predetermined distance from an end of the work piece, for releasing the second clamp from said work piece and operating the first clamp to engage the said work piece to laterally advance the carriage with the work piece until its marginal extremity is folded and presented in operating relation to said work feeding means.

2. Apparatus as set forth in claim 1 wherein the control means includes a sensor mounted on the carriage ahead of the hemmer and responsive to traverse of the end of the work piece adjacent to the instrumentalities for disengaging the second clamp from the work piece and causing the workpiece to be engaged for feeding by the first clamp.

3. Apparatus as set forth in claim 1 wherein the hemmer includes means to direct an air flow therein for urging the folding ofa margin of the work piece parallel to the feeding direction, and a sensor associated with the bed is responsive to presentation of a work piece thereon and adapted to control the air flow.

4. Apparatus as set forth in claim 1 wherein a sensor, responsive to joint advance of the carriage and of the hemmer to fold a work piece margin and present it in effective relation to the feeding instrumentalities, is op; erative to start the sewing machine.

5. The combination with a sewing machine having stitch forming mechanism, a bed, and work feeding means for advancing a work piece linearly on the bed to said mechanism, of a hemming device movable parallel to the direction of work feeding and to the bed, means for holding the work piece stationary on the bed while the hemming device is moving relative to the work, and power means for moving the device relatively to the work and then jointly therewith for sequentially folding an edge of the work substantially up to an extremity thereof and thereafter urging it into the operating zone of the work feeding means.

6. The combination set forth in claim 5 wherein one non-translatory work engageable clamp cooperates with the bed during relative movement of the device with respect to the work, and another work engaging clamp moves in translation with the device when the non-translatory clamp is disengaged.

7. A hemming system comprising, in combination with a sewing machine having a'reciprocable needle, a flat bed, and feed means including a feed dog for advancing a work piece linearly over the bed and through the operating zone of the needle, a fabric feeder including pick-up and deposit devices for delivering from a stack successive work pieces for deposit in approximately predetermined position on the bed and laterally spaced from the needle, a laterally reciprocable hemming device movable parallel to the bed from a work receiving position, a first work engaging means spaced from and jointly movable laterally with the hemming device, a second work engaging means remote from the first and cooperative with the bed temporarily to clamp the deposited work piece in its approximate predetermined position, and power means for jointly moving the hemming device and the first work engaging means toward the needle and relative to the work while the latter is clamped only by the second work engaging means whereby a marginal extremity of the work is folded parallel to its direction of feed in the sewing machine, and control mechanism thereupon operative to engage and disengage the second work engaging means and cause the first work engaging means to advance the folded marginal extremity into the operating zone of the feed dog, said control mechanism being then auto matically operable to initiate operation of the sewing machine.

'8. For use with a sewing machine having work feeding mechanism and a bed, a carriage reciprocable parallel to the bed and toward and from the mechanism, power means for operating the carriage, a sensor, a hemmer, and a work engageable feeder carried by the carriage parallel to the line of feed of the feeding mechanism, a movable work clamp for initially holding the work stationary on the bed when an edge of the work initially is received in the hemmer, and control mechanism responsive to positioning of said work adjacent said sensor for causing the power means to advance the carriage toward the sewing machine, a portion of the control mechanism being operative, when the hemmer has folded the edge of the work to within a predetermined distance from its extremity as measured by said sensor, to release the work clamp and cause the work engageable feeder to engage and advance the folded extremity to the operating zone of the feeding mechanism of the sewing machine. 

2. Apparatus as set forth in claim 1 wherein the control means includes a sensor mounted on the carriage ahead of the hemmer and responsive to traverse of The end of the work piece adjacent to the instrumentalities for disengaging the second clamp from the work piece and causing the workpiece to be engaged for feeding by the first clamp.
 3. Apparatus as set forth in claim 1 wherein the hemmer includes means to direct an air flow therein for urging the folding of a margin of the work piece parallel to the feeding direction, and a sensor associated with the bed is responsive to presentation of a work piece thereon and adapted to control the air flow.
 4. Apparatus as set forth in claim 1 wherein a sensor, responsive to joint advance of the carriage and of the hemmer to fold a work piece margin and present it in effective relation to the feeding instrumentalities, is operative to start the sewing machine.
 5. The combination with a sewing machine having stitch forming mechanism, a bed, and work feeding means for advancing a work piece linearly on the bed to said mechanism, of a hemming device movable parallel to the direction of work feeding and to the bed, means for holding the work piece stationary on the bed while the hemming device is moving relative to the work, and power means for moving the device relatively to the work and then jointly therewith for sequentially folding an edge of the work substantially up to an extremity thereof and thereafter urging it into the operating zone of the work feeding means.
 6. The combination set forth in claim 5 wherein one non-translatory work engageable clamp cooperates with the bed during relative movement of the device with respect to the work, and another work engaging clamp moves in translation with the device when the non-translatory clamp is disengaged.
 7. A hemming system comprising, in combination with a sewing machine having a reciprocable needle, a flat bed, and feed means including a feed dog for advancing a work piece linearly over the bed and through the operating zone of the needle, a fabric feeder including pick-up and deposit devices for delivering from a stack successive work pieces for deposit in approximately predetermined position on the bed and laterally spaced from the needle, a laterally reciprocable hemming device movable parallel to the bed from a work receiving position, a first work engaging means spaced from and jointly movable laterally with the hemming device, a second work engaging means remote from the first and cooperative with the bed temporarily to clamp the deposited work piece in its approximate predetermined position, and power means for jointly moving the hemming device and the first work engaging means toward the needle and relative to the work while the latter is clamped only by the second work engaging means whereby a marginal extremity of the work is folded parallel to its direction of feed in the sewing machine, and control mechanism thereupon operative to engage and disengage the second work engaging means and cause the first work engaging means to advance the folded marginal extremity into the operating zone of the feed dog, said control mechanism being then automatically operable to initiate operation of the sewing machine.
 8. For use with a sewing machine having work feeding mechanism and a bed, a carriage reciprocable parallel to the bed and toward and from the mechanism, power means for operating the carriage, a sensor, a hemmer, and a work engageable feeder carried by the carriage parallel to the line of feed of the feeding mechanism, a movable work clamp for initially holding the work stationary on the bed when an edge of the work initially is received in the hemmer, and control mechanism responsive to positioning of said work adjacent said sensor for causing the power means to advance the carriage toward the sewing machine, a portion of the control mechanism being operative, when the hemmer has folded the edge of the work to within a predetermined distance from its extremity as measured by said sensor, to release the work clamp and cause the work engageable feeder to engage and advance the folded extremity to the operatiNg zone of the feeding mechanism of the sewing machine. 